Almost right
The ECM will still defuel to limit boost and power once the MAP sensor sees over about 20psi of so. Even if the wastegate is turnbuckled shut, there will be only so much fuel [combustion pressure] to create boost. The ECM uses the info from the MAP [Manifold Air Pressure I think] sensor.
The Boost fooler that is either added on or built into a fueling box like the EZ or Comp 'clips' the voltage from the MAP so that the ECM thinks the MAP sensor is reading only 18-20 psi. Therefore the ECM doesn't limit the fueling. With no limiting of the fuel by the ECM and Injection pump, your larger injectors can supply the extra fuel and create the extra power [and extra boost if the wastegate doesn't bleed it off].
If you are getting 1400*, you need more boost [combustion air] to cool down your combustion temps. Once you get a boost fooler or an EZ, you can just plug the wastegate line on your turbo. With just Stage 1 injectors, [and even with an EZ] you won't over speed your turbo, and you won't create enough back pressure [excess drive pressure] to reduce power. Give your engine as much boost as it can create. With your relatively mild extra fueling, the boost will be self limiting.
I was running BD1's, and Edge EZ with the HY35's wastegate hardline plugged, and got only about 34-36 psi boost, and zero ill effects. And saw 1150* as a max EGT. When I set the wastegate to limit boost to 28-30 psi, I saw 1250* EGT's, so I just plugged the hardline, and let the fuel limit the boost, and had cooler EGT temps in the bargain.
Hope this helps, Greg L the Noise Nazi